S25FL004A Meet Spansion Inc., S25FL004A Datasheet - Page 18

• Manufacturer Part Number: S25FL004A
• Description: 4-megabit Cmos 3.0 Volt Flash Memory With 50 Mhz Spi Bus Interface
• Manufacturer: Meet Spansion Inc.

9.5
9.6
18
Write Disable (WRDI)
Read Status Register (RDSR)
The Write Disable (WRDI) command (see
disables the device from accepting a Write Status Register, program, or erase command. The host system
must first drive CS# low, write the WRDI command, and then drive CS# high.
Any of following conditions resets the WEL bit:
The Read Status Register (RDSR) command outputs the state of the Status Register bits.
the status register bits and their functions.
The RDSR command may be written at any time, even while a program, erase, or Write Status Register
operation is in progress. The host system should check the Write In Progress (WIP) bit before sending a new
command to the device if an operation is already in progress.
sequence, which also shows that it is possible to read the Status Register continuously until CS# is driven
high.
Power-up
Write Disable (WRDI) command completion
Write Status Register (WRSR) command completion
Page Program (PP) command completion
Sector Erase (SE) command completion
Bulk Erase (BE) command completion
Bit
7
6
5
4
3
2
1
0
Status Register Bit
SRWD
WEL
BP2
BP1
BP0
WIP
—
—
SCK
CS#
Figure 9.5 Write Disable (WRDI) Command Sequence
SO
SI
Status Register Write Disable
Mode 3
Mode 0
Hi-Z
Write Enable Latch
Write in Progress
Table 9.2 S25FL004A Status Register
Bit Function
Block Protect
S25FL004A
—
—
Figure
0 1 2 3 4 5 6 7
D a t a
9.5) resets the Write Enable Latch (WEL) bit to a 0, which
Command
S h e e t
1 = Protects when W# is low
0 = No protection, even when W# is low
Not used
Not used
000–111 = Protects upper half of address range in 5 sizes. See
Table 7.1 on page
1 = Device accepts Write Status Register, program, or erase
commands
0 = Ignores Write Status Register, program, or erase commands
1 = Device Busy. A Write Status Register, program, or erase
operation is in progress
0 = Ready. Device is in standby mode and can accept commands.
Figure 9.6
13.
shows the RDSR command
Description
S25FL004A_00_B3 July 9, 2007
Table 9.2
shows